The Gasoline Particulate Filter FAQ


Like it or not, emissions regulations will tighten significantly for all fossil fuelled vehicles. This means more technology, more costs and much much more to go wrong.

With the fall out of dieselgate, many motorists are now opting for petrol. In fact record numbers are switching to petrol and alternatively fueled vehicles as the demonisation of diesel powered vehicles continues to gain momentum.

Unfortunately petrol engines haven’t escaped the emissions crack down. The latest advance in petrol emissions control technology is the GPF or gasoline particulate filter. 

What is a GPF Gasoline Particulate Filter

A GPF (Gasoline Particulate Filter) is an inline exhaust filter designed to capture soot particulates in direct injection petrol engines (GDI). Much like a DPF, it comprises of a honeycomb like filter structure made from a synthetic ceramic material.

As exhaust gasses pass through the filter, soot particles are captured. These filters are highly efficient, capturing in excess of 90% of airborne particulates which would otherwise be released into the atmosphere.

In Germany, theses filters are referred to as Otto particle filter (Ottopartikelfilter or OPF)

How is it different to a DPF

Unlike a DPF, a GPF has a very small capacity for captured soot particulate, 1g compared to around 8g for a typical DPF. In contrast, a GDI engine emits around 30 times less particulate than a diesel engine.

How does a GPF regenerate?

GPF regeneration can only be performed in “non power” conditions,  meaning that regeneration is normally achieved under deceleration. Deceleration increases the amount of oxygen following through the engine and exhaust system. This in turn raises the temperature of the GPF to around 400c – 700c, igniting the soot contained within the filter. 

In conditions where this is not possible, the vehicles engine management systems alters timing causing it to run lean. This “lean” burn increases oxygen and therefore GPF operating temperatures, allowing a regeneration to occur.

Ford Owners –Exhaust filter limit reached. drive to clean now“.

As per the comments below – we’ve been made aware of issues with Ford owners experiencing issues with their GPF.

We have put together a new article regarding this issue here –

Do I need to use a GPF additive?

Due to the nature of GPF regeneration, an fuel additive it not required to assist in the cleaning / regeneration of the filter.

How much is a replacement unit?

It’s still very early days for GPFs. We’re hoping that due to the nature of regeneration, failure due to the unit reaching its soot capacity should be relatively rare. However, it is noted that GPF are much more delicate and prone to damage compared to a diesel particulate filter.

Which cars will be fitted with a GPF

So far, the uptake on GPF technology has been rather slow. Mercedes and the VW Group are noted to have rolled out the technology for use in a number of their turbo charged engines. It’s expected that a mass rollout will begin in the next 5 – 7 years.

GPF and Euro 6

With the introduction of euro 6c emissions controls, vehicles will be subject to “real world” driving conditions in order to record realistic emissions results. The particulate limits for petrol engines will also tighten significantly.

It’s hoped that this will force manufacturers into employing new innovative ways in reducing emissions outside of “lab” conditions. A GPF will be just another tool in their arsenal to ensure they meet these new limits. We really don’t want another emissions scandal!

Let’s hear from you

What are your thoughts on Gasoline Particulate Filters? Would this put you off buying a new petrol car? Have you had a GPF fail in your car. Let’s hear from you in the comments below

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Karl is the editor and owner of this glorious website. He currently writes for numerous environmental websites, producing content for the greater good. His experience in graphic design, Wordpress and all things automotive have helped sculpt into its current form from very humble beginnings. He has numerous IT qualifications, a red belt in Taekwondo and likes craft Ales. Get in touch via our Contact Page

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12 comments on “The Gasoline Particulate Filter FAQ
  1. Steffen Holland says:

    Just bought focus 1.0 ecoboost ,brand new 68 plate. Lovely car but had warning message come up after only 300 miles. Bought this car as i thought it would be more economical. If i have to drive up and down the motorway everytime i get this warning this is going to be a right pain in the a**e. Had i known about this before i purchased the car i probably would not have bought it. Obviously this has been a problem for a while now so why was this not mentioned to me by the salesman before he took my £22.000. Feeling very disappointed.

    • Karl says:

      Hi Steffen

      Thanks for getting in touch. Is it definitely the petrol one you have? Have you got a photo of the dash warning light? Does it go into limp home (reduced power mode) when the GPF light comes on?

      Sorry about the questions – it’s the first time we’ve heard about issues with the GPF and we’d like to learn more. We assumed that GPFs required very little maintenance and just sat silent in the back ground.

      Cheers Karl

  2. Pawel says:

    I have this same problem. I bought new Focus 1.0 ecoboost 125 hp and after 4 000 km I get worning message. Now I have almost 7000 km and I have this worning message 3 Times. “dpf has reached the limit. Continue driving to clean up” – even though I have an unleaded petrol engine, I do not have oil…. echh

  3. Mnc says:

    I am owning a Honda Civic 1.0 with GPF, mainly does 100km+ journeys, but also 1km short trips in town. Never had a warning message from GPF, although, each time after 40-50km hard driving (upshifting at 5500rpm), the car does an active regen (stop/start does not work, radiator fan is on, engine idle varies 930-970rpm instead of staying dead center at 950rpm). The weird thing is driving it: often times, under decceleration, the fuel does not cutoff completely, which I find very odd and I think this is related to the GPF somehow.

  4. Fly101 says:

    Any further feedback on the Ford cases? What did the garage say? Interested in knowing how bad it is for future choices…

  5. Phillip Birch says:

    You say above that ” In contrast, a GDI engine emits around 30 times less particulate than a diesel engine.”

    However, research by TÜV NORD* found that although GDI engines dramatically reduce carbon dioxide emissions, they release about 1000 times more particulate matter (classified by the World Health Organization as harmful) compared to traditional petrol engines and 10 times more than new diesel engines. This is also 10 times more polluting than a diesel equipped with a diesel particulate filter (DPF).

  6. Sid ludkin says:

    I bought a 1 litre Ecoboost focus in July 2019 1st September 2018 plate. It had just over 3000 miles on the clock has currently done 4000 miles in total. Over the last few weeks I have had the same problem (exhaust filter at limit drive to clear) I blasted it up the motorway for 20 minutes in lower gears averaging 2500 to 3500 rpm. Next day got same message !! Will have to go to the dealer to see what’s going on.

  7. Michelle Geer says:

    I brought an MG ZS back in June 19, I started to experience lumpy/juddering driving more or less straight away, after several visits back to my dealer and being fobbed off saying it was probably me as I was new to automatics they finally in October 19 received a technical bulletin explaining about the GPF and that the regeneration can cause this lumpy driving and that there is nothing wrong with the car but that it is a characteristic and that I have to change my driving styles (find a motorway once a week to give it a blast). I don’t do motorway driving and I do not expect to have to start with a brand new car! The dealer has now informed me that more and more people are returning to the garage with the same issues, and they are now informing new buyers at the point of sale. I have put a letter of rejection in for the car as I feel as though I have been miss-sold it, as if I had been informed about these driving styles before purchasing it I would never have brought it. I never have a warning light on my dash, but I have lumpy horrible driving everyday !!! I hate my car and will do everything I can to return it. I have now put a case forward with the Motor Ombudsman. more people need to come forward and make a stance.

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